This invention relates to a rotary valve and more particularly to a rotary valve for draining and testing sprinkler systems.
Rotary valves, such as disclosed in U.S. Pat. No. 4,655,078 and U.S. Pat. No. 4,971,108 have been incorporated in sprinkler systems so that the operation of the sprinkler systems can be routinely checked. These rotary valves normally incorporated an actuator handle that is connected directly to a ball member carried within the valve housing. By rotating the actuator arm, the ball valve can be rotated so that different sized passages provide communication between the inlet and outlet of the valve. In normal operation, it was desirable that one passage would permit the flow of water corresponding to the flow of one sprinkler head being activated. The other passage, as shown in U.S. Pat. No. 4,655,078, was of a larger diameter to permit the sprinkler system to be drained by aligning the passage with the inlet and outlet opening of the valve. The valve could also be rotated to a shut-off position where no water was permitted to flow between the inlet and outlet.
Normally the valve is installed in communication with a conduit forming part of the sprinkler system. The test conduit in which the test valve is carried extends from the conduit of the sprinkler system to a drain. During the testing operation, water flows from the conduit of the sprinkler system through the test valve to any suitable drain. It is desirable that sprinkler systems be equipped with a pressure relief valve system so that if the pressure built up within the sprinkler system exceeds a pre-determined pressure then the flow of water would be directed to the drain. In one attempt to solve this problem, a bypass conduit which has a pressure relief valve interposed therein is connected between the inlet and outlet of the test valves being used in the sprinkler system. One problem with this system is that it requires additional plumbing and it must be disconnected when the sprinkler system is being hydrostatically tested at pressures higher than set on the relief valve. This is not a satisfactory solution since the conduit system which includes the check valve is not in place when the system is being hydrostatically tested. An example of one system utilizing a relief valve is manufactured by AGF Manufacturing Company, Model 1011 and Model 3011.